Momentary plunger switch

ABSTRACT

A momentary plunger-type electric switch in which a single plunger return spring performs the simultaneous additional function of returning the switch lever to its initial position. The switch case is made of a pair of identical juxtaposed halfshells which accommodate a unitary contact terminal in either of two positions according as a normally open or a normally closed switch is specified or desired. The device can be utilized as a single-circuit or a two-circuit switch.

United States Patent Inventor Richard W. Sorenson West Hartford, Conn.

Appl. No. 63,715

Filed Aug. 14, 1970 Patented Nov. 9, 1971 Assignee Carling Electric Inc.

West Hartford, Conn.

. MOMENTARY PLUNGER SWITCH 6 Claims, 9 Drawing Figs.

US. Cl 200/ 153 J, 200/ l 59 int. Cl l-l0lh 3/00 Field of Search 200/ 153 J, 159

[56] References Cited UNITED STATES PATENTS 3,165,611 1/1965 Hagberg 200/159 3,016,439 1/1962 Hagberg 200/159 3,277,264 10/1966 Barthell 200/159 Primary Examiner-J. V. Truhe Assistant Examiner-Hugh D. Jaeger Attorney-1. Jordan Kunik minal in either of two positions according as a normally open or a normally closed switch is specified or desired. The device can be utilized as a single-circuit or a two-circuit switch PATENTEDNUV 9 197i 3,619.52 8

SHEET 1 BF 3 INVI'JNI'HR. RICHARD W. SORENSON I PATENTEDuuv 9 19m 3,519,528

sum 3 OF 3 INVI'IN'I'UH.

RICHARD w. SORENSON ATTORNEY MOMENTARY PLUNGER swrrcn BACKGROUND OF THE INVENTION I Field of the Invention This invention relates to a plunger-type electrical switch and, more particularly, to a switch wherein a single, unitary spring element is utilized to perform the function of returning the plunger element to its original position and simultaneously to return the electrical contact lever back to its original position after the plunger has been released. A modular switch case and contact terminal structure makes possible the production of either a normally open or nonnally closed switch for a single circuit, or of a switch for controlling two separate circuits, by using identical parts throughout.

2. Description of the Prior Art Momentary switches of the type embodied in the present invention have been disclosed in the prior art as, for example, in the following US Pat. Nos.: 1,538,882; 2,021,041; 2,047,950; 2,601,545; 3,165,611.; 3,l83,333; 3,213,229; 3,277,264, and 3,321,983.

Typical amongst those switches is the one disclosed in US. Pat. No. 3,165,61 I, wherein the coordinated movements of the plunger and the pivoting of the contact lever are brought about by four spring elements, and wherein a great number of parts are required to bring about these manipulations resulting in a comparatively expensive cost of production and intricate assembly problems.

SUMMARY OF THE INVENTION The disadvantages of the prior art momentary switches are overcome by the apparatus of the present invention wherein a single spring is utilized to operate upon the plunger as well as upon the control element for the pivoting contact member whereby a great number of component parts are eliminated and costs of production and assembly are greatly reduced.

The present invention comprises a pivoting lever contact actuator which is provided with pivotal motion by means of a plunger stem when the latter is depressed and a plunger return spring which not only returns the plunger to its original position but also simultaneously returns the actuator to its original position after the plunger has been released. The improved switch case structure makes possible the assembly of either normally open or normally closed switches with the use of interchangeable modular parts.

These and other novel features and advantages of the present invention will be described and defined in the following specification and claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of the switch of the present invention;

FIG. 2 is a greatly enlarged section view taken on line 2-2 of FIG. 1, some parts being omitted, some parts being shown in elevation and illustrating the nonnally open circuit embodiment of the invention in the open circuit condition;

FIG. 3 is a view similar to FIG. 2 wherein the plunger has been momentarily depressed and the switch is in the closed circuit condition;

FIG. 4 is a view taken approximately on line 4-4 of FIG. 2;

FIG. 5 is a view taken on line 5-5 of FIG. 2;

FIG. 6 is a view taken on line 6-6 of FIG. 2;

FIG. 7 is a further enlarged fragmentary view of a portion of the return spring incorporating a reinforcing element thereon;

FIGS. 8 and 9 are fragmentary views comparable to FIGS. 2 and 3, showing a normally closed embodiment of the switch, and wherein the plunger is in the retracted position in FIG. 8, and in the momentarily depressed position in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in detail, the switch of the present invention comprises a housing generally designated 11 which is made of a pair of identical juxtaposed half-shell cases,

each of which comprise end walls 12, top walls 13, sidewalls l4, and floors 15, said cases forming therebetween a switch chamber 16. The two half-shell cases are aligned with each other by means of a recess l7 which accommodates an integrally formed protruding pin 18 on the opposing half-shell case. The two half-shell cases are made of a suitable insulating material such as nylon, Bakelite, or the like.

Thehalf-shell cases are secured together by means of a sheet metal cover element 24 having downwardly extending, integrally formed legs 26 nested in suitable recesses in the outer walls of said cases, each of said brackets terminating in spaced apart fingers 27 which are bent inwardly into recesses 28 in sidewalls 14 to secure said cover element and said legs in position.

Located in floor 15 of each half-shell case approximately centrally between end walls 12 is a vertical slot 29, said slots jointly accommodating the shank of an electrically conductive combined terminal yoke 31, the lower portion of which extends through floor Sand to which a lead line of the electrical circuit to the be controlled by said switch may be connected. Upset from the shank of terminal yoke 31 is a pair of laterally extending spaced apart legs 32 which fit into horizontal respective slots 33 in the floor 15 of each half-shell case. Although legs 32 are upset in one direction only, it will be noted that slots 33 are aligned on both sides of slot 29 so that said legs may be arrayed in either the left-hand or right-hand direction, depending upon convenience of assembly. Legs 32 serve the purpose of stabilizing the vertical position of terminal yoke 31. a

The upper end of terminal yoke 31 is formed into a pair of upwardly extending, space-apart fingers 34 which bound a horizontal shoulder 36, see FIG. 4. Pivotally supported on shoulder 36 is an electrically conductive switch lever, generally designated 37, which has a pair of notches 38 in the opposite sides thereof which loosely accommodate fingers 34 whereby said lever is retained on the yoke. The middle portion of lever 37 is V-shaped to form a pair of camming elements 39 and 41. One end of lever 37 terminates in a blank arm 42 while the other end of said lever terminates in a contact button 43.

Formed in the interior of each half-shell case on both ends thereof above floor 15 are bosses 44 which have vertical recesses 46 formed therein. Also fonned in bosses 44 are horizontal recesses 47 which intersect respective recesses 46. Fitting into horizontal recesses 47 of both opposing shell cases on one side of the assembly thereof is a lateral electrically conductive contact terminal member generally designated 48 which, intermediate its ends, has a pair of spacedapart upwardly extending legs 49 that fit snugly into vertical recess 46, said legs 49 serving to stabilize the horizontal position of contact terminal 48. The inner end of contact terminal 48 terminates in an upwardly extending contact element 51 while the other end 52 of member 48 extends outwardly from the switch case whereby a lead line from a circuit to be controlled by said switch may be connected It will be noted that the unitary member comprising terminal 48 and contact 51 may be interchangeably inserted at will during assembly of the switch into either one of the other sidewalls 12 of the mated half-shell cases as shown in FIGS. 2 and 8, depending upon whether the device is to perform as a normally open or a normally closed switch.

The roof of each half-shell case has a central aperture 53 above which is located a bushing 54 which is firmly connected by means of annular collar 56 of cover plate 24 cooperating with flange 57 of bushing 54. Bushing 54 has a vertical slot 58, the lower end of which is engaged by a nib 59 on collar 56 to prevent rotation of said bushing relative to collar 56.

Movable longitudinally within the interior of bushing 54 is a plunger 61, the lower end of which has an integrally formed, outwardly extending annular boss 62, the upper edge of which cooperates with an inwardly extending shoulder 63 in the interior of bushing 54 whereby the upward movement of plunger 61 is limited, as shown in FIG. 2.

The lower portion of plunger 61 has an axial recess 64, the upper end of which terminates in a conical cavity 66. Located within recess 64 is an axially extending elongated plunger stem 67, the upper end of which terminates in an integrally formed conical cap 68 which fits'snugly within conical cavity 66.

A lever actuator 71 is pivotally mounted by means of integrally formed, oppositely extending pins 72 in recesses 73 in respective sidewalls 14. The upper portion of actuator 71 has an inverted V-shape in the form of surfaces 74 and 76, see FIGS. 2, 3 and 4. Extending in opposite directions partially across the surfaces 74 and 76 of actuator 71 fromthe apex thereof are respective inclined recesses 77 and 78 located intermediate the sidewalls of said actuator.

The bottom central portion of actuator 71 has a longitudinal recess 81 which accommodates a longitudinally movable nib 82. Nib 82 has a longitudinal recess 83 which accommodates a captive spring 84, the upper end of which bears against the upper end of recess 81 and the lower end of which bears against the bottom end of recess 83, thereby urging the lower end of nib 82 against either camming elements 39 and 41 of lever 37, depending upon the operation of plunger 61. Both actuator 71 and nib 82 are made of suitable insulating materials such as nylon, Bakelite, or the like.

Coiled around stem 67 is a spring 86, the upper end of which bears against the bottom surface of cap 68 while the lower end thereof terminates in a downwardly extending finger 87, the end of which abuts against and is engaged by the end wall 88 of recess 78 in lever actuator 71. The normal action of spring 86 is to retract plunger 61 upwardly and to bear upon wall 88 to cause actuator 71 to be pivotally turned clockwise to the left, as shown in FIG. 1. In this position, recess 77 is located directly beneath the lower end of stem 67.

When plunger 61 is depressed momentarily against the action of spring 86 as shown in FIG. 3, the lower end of stem 67 moves downwardly and slides within recess 77 until it comes into abutment with the end wall 89 of said recess thereby causing lever actuator 71 to rotate counterclockwise whereby nib 82 moves slidably from cam element 39 to cam element 41. By this action, switch lever 37 is moved pivotally so that button 43 comes in contact with contact element 51, thereby closing the electrical circuit between terminal 52 and terminal 31, momentarily.

When plunger 61 is depressed, the pivotal motion of cap 68 outwardly from cavity 66 permits the sidewise motion of stem 67 as the lower end thereof slides into recess 77 and abuts wall 89 thereof, as shown in FIG. 3. Although stem 67 is illustrated in the drawings as being made of stifi metal, it is comprehended that in some embodiments said stem may be integrally formed with the main body of plunger 61 when the latter is made of a plastic material whereby said stem would be somewhat resilient and flexible and could bend in accommodating to its coaction with recess 77 in actuator 71.

When plunger 61 is released, spring 86 causes the upward movement of said plunger together with stem 67 which becomes retracted from recess 77 while simultaneously spring finger 87 causes the clockwise return rotation of lever actuator 71 back to its original position, as shown in FIG. 2. During this action, nib 82 slides from camming element 41 to camming element 39 to cause the pivoting action of lever 37 to its open circuit position, as shown in FIG. 1. Arm 42, under the pressure of nib 82, is urged and comes to rest against a suitable boss 91 formed integrally in the interior of the halfshell cases.

When stem 67 is moved pivotally during the depression of plunger 61 (FIG. 3), cap 68 moves partially away from conical cavity 66, but when said plunger is released, the upper end of spring 86 causes cap 68 to return into said cavity as shown in FIG. 2 whereby stem 67 resumes its normal, vertical position.

Although finger 87 of spring 86 may be sufficiently stiff to perform its function in rotating lever actuator 71, it may be desirable in some cases to ensure the proper function of finger 87 by reinforcing it with a snugly fitting tubular sleeve 92 made of a suitable metal or plastic tubing, the lower end of said sleeve being substantially contiguous with the lower end of finger 87, see FIG. 7. Further reinforcement of finger 87 may be provided by a flange 93 formed integrally on sleeve 92 which extends around and supports the interior surface of the knuckle 94 of finger 87.

Because of the identical symmetry of the half-shell cases, the normally open switch embodied in FIGS. 1 and 2 can be readily transformed into a normally closed switch as embodied in FIGS. 8 and 9. All that is required is to reverse the position of switch lever 37 on terminal yoke element 31 and to transpose the location of element 48, comprising contact 51 and terminal 52, from the right side of the switch assembly assembly to the left side. Accordingly, by manufacturing identical component parts, a customers order for either normally open, or normally closed, momentary plunger switches can be executed on the assembly line by simply reversing the positions of lever 31 and the contact terminal element 48 in the assembled switch case. Furthermore, recesses 77 and 78 in actuator 71 are symmetrically arrayed in respective surfaces 74 and 76 whereby assembly of the switch is facilitated since either of said recesses may be engaged by either spring finger 87 or by the lower end of spindle 67. The device herein may also be transformed from a normally open, to a normally closed switch, or vice versa, in that manner on the installation site.

It is understood that in some embodiments where the switch is to control two active circuits, terminal contact element 48 may be inserted in both slots 47 on both sides of the switch, and lever arm 42 would be provided with a contact button similar to button 43 whereby the two separate circuits to which the separate elements 48 are connected may be activated selectively through a common power line connected to terminal yoke element 31.

Although the present invention has been described with reference to particular embodiments and examples, it will be apparent to those skilled in the art that variations and modifications can be substituted therefor without departing from the principles and true spirit of the invention. The Abstract given above is for the convenience of technical searchers and is not to be used for interpreting the scope of the invention or claims.

lclaim:

l. A momentary switch comprising a case, a contact lever pivotable within a said case between two circuit positions, a pivotable actuator in said case and operative on said contact lever, a reciprocable plunger on said case, a spring positioned between said plunger and actuator normally causing the retraction of said plunger and simultaneously operative on said actuator to cause the latter normally maintain to said lever into one of its two positions, said plunger when momentarily depressed engaging said actuator to pivotally move the latter against the action of said spring in the opposite direction against the action of said spring whereby said actuator pivotally moves said lever into the other one of its two positions.

2. A switch according to claim l wherein said actuator comprises a pair of oppositely extending first and second recesses, said first recess being normally and continuously engaged by said spring and said second recess being momentarily engaged by said plunger.

3. A switch according to claim 2 wherein the actuator is normally maintained under the action of said spring in a position where said second recess is directly opposite said plunger.

4. A switch according to claim 1 wherein said plunger comprises an elongated stem and said spring is in the form of a coil, one end of which bears against the upper end of said stem and the other end of which is formed into a downwardly extending finger, said finger continuously engaging said actuator to yieldably maintain the latter normally in one of its two positions.

5. A switch according to claim 4 and further comprising a close-fitting tubular sleeve surrounding said finger for reinforcing the latter.

6. A switch according to claim 5 wherein said finger is bent at an angle relative to said coil, and said sleeve has an integral flange at one end thereof supporting the juncture between said finger and said coil.

1' k K I 5 

1. A momentary switch comprising a case, a contact lever pivotable within said case between two circuit positions, a pivotable actuator in said case and operative on said contact lever, a reciprocable plunger on said case, a spring positioned between said plunger and actuator normally causing the retraction of said plunger and simultaneously operative on said actuator to cause the latter normally to maintain said lever into one of its two positions, said plunger when momentarily depressed engaging said actuator to piVotally move the latter against the action of said spring in the opposite direction against the action of said spring whereby said actuator pivotally moves said lever into the other one of its two positions.
 2. A switch according to claim 1 wherein said actuator comprises a pair of oppositely extending first and second recesses, said first recess being normally and continuously engaged by said spring and said second recess being momentarily engaged by said plunger.
 3. A switch according to claim 2 wherein the actuator is normally maintained under the action of said spring in a position where said second recess is directly opposite said plunger.
 4. A switch according to claim 1 wherein said plunger comprises an elongated stem and said spring is in the form of a coil, one end of which bears against the upper end of said stem and the other end of which is formed into a downwardly extending finger, said finger continuously engaging said actuator to yieldably maintain the latter normally in one of its two positions.
 5. A switch according to claim 4 and further comprising a close-fitting tubular sleeve surrounding said finger for reinforcing the latter.
 6. A switch according to claim 5 wherein said finger is bent at an angle relative to said coil, and said sleeve has an integral flange at one end thereof supporting the juncture between said finger and said coil. 